Rotary shaft seals enable a rotating shaft to pass through an enclosure while blocking the flow of a fluid such as oil or water. In some systems an elastomer of annular shape provides the required sealing function; such seals are commonly referred to as lip seals. For applications where the shaft surface speeds are relatively low (e.g. less than 2 m/second), such seals may perform adequately. However, for high speed applications (e.g. greater than 20 m/second), lip seals may encounter several problems, including that (i) drag and drag related losses may become excessive, especially when sealing against liquid pressures which are more than a few kPa, (ii) temperature rise may become excessive, and (iii) the service life of the lip seal may become unacceptably short.
Thus, there is a need for an improved seal for a rotating shaft.